<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <link rel="stylesheet" href="./bootstrap/bootstrap.min.css" />
    <style>
      .container-fluid {
        height: 1000px;
        background-color: pink;
      }

      .row div {
        border: 1px solid #000;
      }
    </style>
  </head>
  <body>
    <!-- 
      栅格系统：
        一行分为12等份
      响应式尺寸
        xs <576px
        sm ≥576px 
        md ≥768px
        lg ≥992px
        xl ≥1200px
        xxl ≥1400px
     -->
    <!-- https://v5.bootcss.com/docs/layout/containers/ -->
    <div class="container-fluid">
      <!-- 自动等分 -->
      <div class="row py-4">
        <div class="col">111</div>
        <div class="col">222</div>
        <div class="col">333</div>
        <div class="col">444</div>
      </div>

      <!-- 一行分为12等份 -->
      <div class="row">
        <div class="col-1">111</div>
        <div class="col-4">222</div>
        <div class="col-3">333</div>
        <div class="col-4">444</div>
      </div>

      <div class="row">
        <div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 col-xl-2">111</div>
        <div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 col-xl-2">222</div>
        <div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 col-xl-2">333</div>
        <div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 col-xl-2">444</div>
        <div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 col-xl-2">555</div>
        <div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 col-xl-2">666</div>
        <div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 col-xl-2">777</div>
        <div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 col-xl-2">888</div>
        <div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 col-xl-2">999</div>
      </div>
    </div>
  </body>
</html>
